Core barrel construction



p 19, 1939- w. E. BOYD 2,173,676

CORE BARREL CONSTRUCTIDN Original Filed Aug. 22, 1932 fun/v PatentedSept. '19, 1939 UNITED. STATES PATENT OFFICE coma BARREL ooNsmUo'noNWilliam E. Boyd, Shreveport, La., assignor to The Brewster Company,Inc., Shreveport, La a corporation 19 Claims.

The invention relates to an improvement in core barrels, particularly ofthe wire line type wherein the core barrel is removable upwardly throughthe drill stem so that the core can be obtained I 5 without withdrawingthe drill stem from the well bore.

It is one of the objects of the invention to provide a core barrel whichwill beresiliently mounted in the drill bit so that it may yield whenoccasion arises therefor.

Another object of the invention is to provide a drive bushing to receivethe core barrel, and serve as a yieldable mounting therefor in the drillstem.

Another object of the invention is to provide a core barrel including adrive bushing which is yieldably mounted in the drill stem for movementeither upwardly r downwardly.

Another object of the invention is to provide in combination with adrill bit and core barr el a spring to absorb the shock of the landingof the core barrel when it is dropped into the drill stem.

Another object of the invention is to provide a combination d'rivebushing and hold-down member for core barrels.

Still another object of the invention is to provide a simple andeconomical construction of the core barrel wherein a single element inthe drill stem serves to both drive and hold the core barrel inposition.

It is also an object of the invention to resiliently mount the corebarrel so that it may move ahead of the drill bit, flush with the drillbit or work in a position retracted into the drill bit.

Another object of the invention is to provide a drive bushing and ahold-down bushing, both of which are positioned in the drill stem tohold the core barrel in core-cutting position.

Other and further objects of the invention will be readily apparent whenthe following description is considered in connection with theaccompanying drawing wherein:

Fig. 1 is a vertical sectional view of the drill stem and drive bushingshowing the upper portion of the core barrel mounted therein.

45 Fig. 2 is a continuation of Fig. 1 and showing the lower end of thedrill stem, the drill bit, and the lower end of the core barrel.

Fig. 3 is an edge elevation of the latching mechanism used to hold thecore barrel in position in the drive bushing.

Fig. 4 is a section taken on the line 4-4 of Fig. 3 and looking in thedirection of the arrows.

Fig. 5 is a vertical section of the lower end of the drive bushing andshowing the drive lugs positioned therein to receive complementary lugson the core barrel.

Fig. 6 is a section taken on the line 8-8 of Fig.

5, and looking in the direction of the arrows.

Fig. 7 is a broken elevation of the core barrel 5 showing the drivinglugs thereon which mesh with the keys in the drive bushing.

Fig. 8 is a section taken on the line 8-8 of Fig.

7 and looking in the direction of the arrows.

By having reference to Figs. 1 and. 2, an entire 10 sectional view ofthe drill bit, drill stem, and portions of the core barrel will be seen.

The drill bit is indicated generally at 2 and may comprise a fish tailbit, as shown, or it may be any other form of core d'rill, many of whichare 15 well known. This drill embodies the blades 3 and the central bodyportion 4. The body portion is hollow, as at 5, to provide a passage forthe flushing fluid passing down through the drill stem and the drillbit. The discharge ports 6 lead from 20 the central passage 5 in adownwardly and outwardly inclined direction so that the flushing fluidwill be directed away from the cutting edge I of the core barrel 8. Inthis manner it has been found that the core barrel need not extend ahead25 of the cutting face 9 of the drill bit and that satisfactory corescan be obtained even in soft formations without forcing the core barrelto extend ahead of the drill bit. The core barrel extends through thebody portion 5 by way of .the 30 central bore H], which is preferably ofa. rather close lit with the core barrel so that there will not be anymaterial amount of flushing fluid pass through the central openingaround the core barrel. 35 Connected to the drill bit 2 is the drillcollar or lower end of the drill stem Hi. This element may be of anydesired length depending upon the length of the core barrel to beemployed. The general practice in the field is to extend the 40 lengthof this drill collar and to make the same as rigid as possible, whichaids in obtaining a straight hole because of the rigidity of this memofrelatively heavy material and of any desired length. The drill collarhere illustrated is provided with a central opening, l6, which isarranged to receive the core barrel and its associated parts. The lowerend of this passage terminates in the discharge ports ll, which permitthe flow of flushing fluid into the drill bit passage 5. The core barrelextends through the opening l8 in the central lower end of the drillcollar l5. A shoulder I9 is provided as defining the end of the passagel'! and the end of the passage I8. Seated upon this shoulder l9 will befound the shock absorbing spring or resilient member which is positionedin the passage I6 and has its upper end 2| abutting against the lowerend 22 of the drive bushing 23.

The drive bushing 23 is mounted in the passage I6 01 the drill collarand is arranged for vertical sliding movement with respect to the drillcollar, but it compelled to rotate with the drill collar by means of thepin 25 and the slot 26. The pin is carried by the drill collar and theslot 26 is formed in the drive bushing 23.

While the term drill bit is generally applied to the bit head, and thenext section termed the drill collar, it is intended in this descriptionthat the term "drill bit or "drill" may include the bit head as well asthe drill collar.

Fig. 5 shows the drive bushing as a short sleeve which is independent ofthe hold-down bushing or hold-down member, which will be presentlydescribed.

The spring 20 is particularly provided to absorb. the shock of landingof the core barrel in its drilling position. The core barrel, it is tobe understood, strikes the drive bushing with considerable force when itlands in position because it has fallen by gravity through the column offlushing fluid inside of the drill stem.

The core barrel 8 is provided with the drive lugs 30 and 3|, and theremay be two or more of these lugs as desired. The lug 30 is preferablysomewhat longer than the lug 3| so that it will strike the drive bushingbefore the lug 3| and tend to rotate the core barrel so that it willpass into its operative position. The lug 3| is seen in side elevationin Fig. 7 and in front elevation in Fig. 2 and preferably comprises astraight vertical portion 32 and the head or stop portion 33. The head33 is shown as tapered inwardly on its upper end as at 34 so that itwill not serve as an obstruction when the core barrel is being withdrawnupwardly through the drill stem. The lower ends of the lugs 30 and 3|are tapered as at 35, so that the core barrel will pass into the corecutting position in the drive bushing 23.

The internal construction and arrangement of the drive bushing 23 isbest seen in Fig. 5 and includes the driving keys 36, which are taperedat 31 in order to guide the drive lugs 30 and 3| into the keyways 38between the keys 36. The lugs and keys are shown in their operative orworking position in Fig. 2 with the straight portion 32 of the lugs inthe keyways 38. The upper end of the bushing 23 is tapered at 39 so thatthe core cutter or lower end of the core barrel will be guided into thedrive bushing. The head 33 on the drive lugs is of greater width thanthe body 32 so that it will land upon the upper endsv 31 of the keys 36and limit the downward movement of the core barrel with respect to thedrive bushing. Upward movement, however, of the core barrel with respectto the drive bushing is not limited in any manner by the lugs and keys.It should be remembered that the drive bushing 23 can move downwardlyfrom the position shown in Fig. 2 because of the spring 20 and the slotand pin connection with' the drill collar l5.

Attention is directed to the fact that there are preferably four of thekeys 36 so that each lug is embraced by two of the keys and that thekeyways 38, on the opposite sides of the keys engaged, are open forpassage of flushing fluid.

The drawing herein shows the drive bushing 23 as made separate anddistinct from the holddown bushing or member 40. The hold-down bushing,however, is positioned in the passage IS in the drill collar the same asthe drive bushing 23. Fig. 2 shows the adjacent ends of the drivebushing and the hold-down bushing as abutting together at 4|. It isintended, however, that the drive bushing and hold-down bushing may bemade as a'single integral member if desired. The hold-down bushing 40may be of considerable length and extends upwardly in the drill collarl5 to hold the core barrel in position against upward movement withrespect to the drive bushing. This hold-down bushing is resilientlymounted in the drill collar because it abuts against the drive bushing23 which can move downwardly and is held against upward movement by thespring 42, which is passed into the drill collar |5 directly above thehold-down bushing. This spring 42 abuts against the drill sub 43, whichis threaded into the upper end of the drill collar IS. The sub 43 servesas a connection for the succeeding joints of drill stem which extend tothe surface in a manner well known.

With the foregoing construction it will'be seen that the drive bushingand hold-down bushing are supported for sliding movement with respect tothe drill collar in which they are mounted and that the hold-downbushing may rotate with respect to the drill collar if desired.

The core barrel 8 extends upwardly and is closed at its upper end bytheplug 45 except for a small passage or vent 46, which is closed by theusual type of ball valve 41 to prevent the entrance of flushing fluidfrom above but to permit the escape of gases or accumulated fluid in thecore barrel at the time the core is being taken.

Directly above the plug 45 is the latching mechanism indicated generallyat 50. This mechanism is best seen in Figs. 3 and 4 and includes thelower connection 5|, which is threaded or otherwise connected to thehead of the core barrel. The upper end of the latching mechanismincludes a head 52, which is arranged to receive the retrieving device54, which will be later described. The heads 5| and 52 are provided withpivot pins 55 and 56, respectively. These pivot pins are arranged toreceive the latching levers 51 and 58. These levers are so constructedthat they will move laterally of the vertical plane of the latchingdevice 50. The lower ends of the levers are pivoted on the pin 55 andcan oscillate upon such pin. The upper ends of the levers are confinedfor very slight lateral movement by the pin 56, which is mounted in theeccentric openings 53. This opening is so designed that it has aninclined surface 58, a straight surface 59, and a. second inclinedsurface 60.

Due to this arrangement, the upper head 52 is slidably mounted withrespect to the levers and the lower head 5|.

When the core barrel is to be positioned it is dropped into the drillstem and fallsby gravity or is forced down by pump pressure to thebottom of the drill stem. It is the experience that the core barrelfalls with considerable speed by the force of gravity. As the corebarrel passes into the hold-down bushing the levers 51 will be movedinwardly to the position shown in Fig. 4 with the head 52 in itsuppermost position. When, however, the drive lugs land in the drivebushing the downward movement of the core barreland the head 5| as wellas the levers 51 opposite direction from the lever 51.

What is claimed is: s,

will be halted. The head '2 by the force of gravity, however, willcontinue its downward movement and the pin 58 will move down in theslots 51. The pin will travel along the straight surface 59 and strikethe inclined surface 0. The continued downward movement of the pin 58will cause the lover I! to move outwardly so that the base 6! of theslot will move into a central'position along a central line of thelatching mechanism. In this manner the corner 52 or i the lever willmove outwardly to the position shown in Fig. l. The lever 58 isidentical with the lever 51 except that its position is reversed, sothat it will be .caused to move laterally in the Fig. 1 shows the twolevers in extended position to latch the core barrel to the hold-downmember 40. When it is desired to retrieve the bore barrel after the corehas been taken, a lifting tool or overshot is connected to theretrieving mechanism 54 and the head 82 is raised. The raising of thishead raises the pin 56 which travels along the inclined face 58 to camthe levers back to their retracted position shown in Fig. 4.

This movement withdraws the corners 62 into a position shown in Fig. 4,so that they are within the confines of the slot u inthe head and theouter surface or edge 64 of the head serves to protect the levers sothat they will not serve as obstructions in withdrawing the core barrel.

The upper end of the drive bushing 40 is formed with a head 66, whichprovides a shoulder 61 beneath which the corner 62 of the latchinglevers are arranged to engageas seen in Fig. 1. The opening through thehead 66 is of sufficient area to permit a flow of flushing fluid throughthe hold-down bushing around the core barrel.

The upper end of the core barrel is provided with the retrievingmechanism shown generally at 54, which includes the barrel 10. Thisbarrel receives the stem II, which is provided with a head 12 to receivethe overshot or retrieving tool which is lowered into the well when thecore barrel is to be removed. The particular form of this retrievingmechanism is shown and described in my co-pending application Serial No.628,464; filed August 12, 1932, and is adapted to release the overshotin event the core barrel is hung or stuck in the drill bit or bushing.This same prior application alsoclaims broadly the yieldable drivebushing.

It will be noted that practically all of the parts positioned inside ofthe drill stem are beveled or streamlined so that'resistance to the flowof fluid is minimized. The mounting of the drive and hold-down bushingsbetween the springs 20 and 42 permits it to float in accordance with thepressures applied either from above or below so that the cutter may beahead, flush with, or retracted into the drill bit.

The present invention contemplates broadly the positioning of acombination drive and holddown bushing which is yieldably mounted in-thedrill collar so that the shock of landing of the core barrel will beabsorbed and the core barrel will be held yieldably against theformation so that the same will not be destroyed by the application ofexcessive pressure from the drill stem. With the present construction astandard form of drill collar may be used and it is only necessary toprovide the additional bushings,

springs and core barrel, in order to adapt the 75 construction for use.

1. A wire line core barrel !or use in combination with a core drill'andstem including a barrel portion to be droppd into the core drill, fixedlugs on said barrel, a bustling slidably but nonrotatably mounted insaid" stem, lixed spaced lugs in said bushing whereby said barrel iscaused to rotate with said stem; said. bushing being yieldably mountedto movedownwardly to absorb the shock of receiving said 2. In a wellcoring assembly, a drill stem and drill bit, a drive bushing and ahold-down bushing disposed in said stema'iid adapted to drive and holdthe core barrelia'nd means yieldabiy supporting said bushings for"movement upwardly or downwardly with respedt-to said drill stem.

3. In the combination oi a core drill and core barrel, a drive bushingcarried by the core drill to impart rotation to the cbre barrel, andmeans resiliently supporting said bushing for vertical sliding movementwith the 'core barrel.

4. In the combination or a drill and core barrel, a drive bushing torotate the core barrel, a

hold-down bushing to ho'lii the core barrel in core cutting position,and--spring means above and below said bushings whereby they may movewith the core barrel in response to pressures thereon.

5. A hold-down mechanism for core barrels including a bushing in thedrill, means on the core barrel to latch; into said bushing to hold thecore barrel down, said core barrel being releasable upwardly from saidbushing and yieldable means to hold said bushing.

6. The combination of a drill collar adapted to receive a core barrel,aoore barrel drive bushing therein, and a resiliently mounted,longitudinally slidable core barrel hold-down bushing also in said drillcollar. h

7. The combination of a drill collar adapted to receive a core barrel,a'bo're barre'fdriv'e bushing therein, a core barrel hold-down bushingalso in said drill collar, and resilient means disposed in said drillcollar to hold said bushinss in a floating position.

8. In a core drill-coreba'rrel combination, a drive bushing to yieldablyrestrain the core barrel against downward movement, and a hold-downbushing to yieldably restrain the core barrel" rotation of said bushingand said collar, a

core barrel insertible downwardly through said 'drill and said bushing,inter-engaging means to prevent rotation of said core barrel in saiddrive bushing, a hold down bushing engaging said drive bushing and saidcore barrel, and a spring to hold them resiliently downward.

.10. A core drill, a drill collar thereon, a drive bushing resilientlymounted in said drill collar, 2. hold down bushing above said drivebushing, and a core barrel insertible downwardly through said bushings,and adapted to engage therewith, both or said bushings beinglongitudinally movable in said drill collar.

11. A device of the character described for use with a core drill andcore barrel assembly-including a vertically slidable drive bushingengaging about said core barrel to cause rotation'oi the core barrelwith the core drill and a holddown bushing to receive said core barreland engage above said drive bushing and about said core barrel and holdsaid barrel in core-cutting position.

'12. A device of the character described for use with a core drill andcore barrel assembly including a drive bushing slidable vertically insaid drill and engaging said barrel to cause rotation of the core barrelwith the core drill, a holddown bushing, resilient means to hold saidholddown bushing against said drive bushing and thus hold the corebarrel in core cutting position, and separate devices carried by thecore barrel to engage both of said bushings.

13. In a core drilling assembly a core barrel of the character describedincluding a core cutter on the lower end thereof, said barrel beingadapted to be dropped into the drill stem to fall to core cuttingposition, and cushionmeans to receive said core barrel and absorb theshock of landing.

14. In a core drill and core barrel assembly, a cushion means carried bythe core drill, the core barrel being adapted to be dropped into thedrill stem to fall to the core drill, said cushion means serving toabsorb the shock of landing.

15. In a rotary drill of the class described the combination including adrill stem having a sleeve mounted interioraly thereof and arranged foryieldable movement in the direction of the axis of the drill stem andbeing non-rotatable with respect thereto, an interior abutment thereinspaced from said sleeve, of a core barrel assembly arranged to beinsertable within and removable from said drill stem having a boringtool normally extending below the end of the drill stem, and means onsaid core barrel assembly arranged to engage the abutment on said drillstem to limit movement of said core barrel assembly past said sleeve inthe direction of said abutment, and means on said core barrel assemblyarranged for releasable engagement with said sleeve.

16. In a rotary drill of the class described the combination including adrill stem having a sleeve mounted interiorally thereof and arranged foryieldable movement in the direction of the axis of the drill stem andbeing non-rotatable with respect thereto, an interior abutment thereinspaced from said sleeve, of a core barrel assembly arranged to beinsertable within and removable from said drill stem having a boringtool normally extending below the end of the drill stem, and means onsaid core barrel assembly arranged to engage the abutment on said drillstem to limit movement of said core barrel assembly past said sleeve inthe direction of said abutment,

and means on said core barrel assembly arranged for releasableengagement with said sleeve whereby said core barrel assembly isyieldably urged toward said abutment.

1'7. In a rotary drill oi the class described the combination includinga drill stem having a sleeve mounted interiorally thereof and arrangedfor yieldable movement in the direction of the axis of the drill stemand being non-rotatable with respect thereto, an interior abutment, of acore barrel assembly arranged to be insertable within and removable fromsaid drill stem having a boring tool normally extending below the end ofthe drill stem, and means on said core barrel assembly arranged toengage the abutment on said drill stem to limit movement of-said corebarrel assembly past said sleeve in the direction of said abutment, andmeans on said core barrel assembly arranged for releasable engagementwith said sleeve whereby said core barrel assembly is yieldably extendedbeyond the end of the drill stem.

18. In a rotary drill of the class described the combination of a drillstem assembly having an internal sleeve, said sleeve being arranged forlimited longitudinal movement with respect to said stem, and beingnon-rotatable independently of said stem; yieldable means interioraly ofsaid drill stem assembly urging said sleeve longitudinally thereof; anabutment interiorally of said assembly and spaced from said sleeve; acore barrel assembly arranged to be insertable within said drill stemassembly and removable therefrom and means releasably interconnectingsaid core barrel assembly and said sleeve whereby said core barrelassembly is yieldably urged beyond the end of the drill stem assembly.

19. A rotary drill including a drill stem, a core barrel rotatable withthe drill stem and normally projecting below the latter, and means fordetachably securing the core barrel with the stem, said .meanscomprising a sleeve carried by the drill stem and reciprocable therein,a spring in the drill stem, and a latch movably mounted on the corebarrel for engaging said sleeve to prevent upward movement of the corebarrel with respect to the sleeve, said spring serving to exert adownward pressure upon the sleeve and to yield upwardly when hardformations are encountered by the core barrel to permit the core barrelto withdraw into the drill stem.

WILLIAM E. BOYD.

